Conduct studies of activation of blood coagulation by the cell surface coat (glycocalyx). Isolate and culture human endothelial and smooth muscle cells (derived from umbilical veins) and fibroblasts (derived from human foreskin) to produce monolayer cultures and glycocalyx material for each cell type. Determine whether or not microexudates have chemical and biological identity with the cell surface coat, using radioautographic and histochemical techniques, and assess tissue factor activity. Determine if monolayer cultures of any of the 3 cell types aggregate platelets and what conditions disturb the monolayer culture enough to provoke platelet aggregation. Determine if undisturbed monolayers of the 3 cell types bind purified factor VII or purified factor XII and if activation of the extrinsic system is a consequ ence of this binding. Using purified factor XII, determine the structural changes after incubation with cell monolayer before and after pertubation and with components of the cell culture.